simple halide group

Halide minerals are naturally occurring inorganic compounds that are salts of halogen acids. While many halide minerals are rare, some, like halite (rock salt), sylvite, and fluorite, are more common.1

Halide minerals are classified by the large anions of halogens: chlorine, bromine, iodine, and fluorine. These ions have a negative charge and combine with cations. When paired with large, weakly polarizing cations like alkali metals, they form highly symmetrical structures. These minerals are typically soluble in water, have low hardness, and moderate to high melting points.1

Common examples include halite (sodium chloride), sylvite (potassium chloride), chlorargyrite (silver chloride), cryolite (sodium aluminum fluoride), fluorite (calcium fluoride), and atacamite. Halite, for instance, forms in beds from the evaporation of saline water and is associated with limestone, dolomite, and shale.12